Research On Treatment Of Dyeing Wastewater By Micro-electrolysis

Dyeing wastewater is one of the major sources of industrial emission in our country. It has the characteristics as follows:deep color, high concentration of COD, poor biodegradation respiration graph, and so on. It is hard to be treated by traditional bio-treatment. Therefore, to protect the environment, it has great significance to study the treatment methods and operating conditions of the dyeing wastewater.The paper focuses on two different kinds of micro-electrolysis reactive material, iron-carbon and aluminum-carbon, each dealing with acidic red and basic violet dyeing waste-water. When use the iron-carbon to treat the acidic red dyeing wastewater, the removal rate of color and COD can be respectively up to 96.4% and 65.45%, under the optimum condition that the value of pH is 3, iron-carbon ratio is 2 to 1, the hydraulic retention time is 60 minutes.When use the aluminum-carbon, the average removal rate of color and COD can be respectively up to 95% and 56%, under the optimum condition that the value of pH is 6, iron-carbon ratio is 1 to 2, the hydraulic retention time is 3 hours.The paper also studies the affection of different kinds of dye on the color removal rate. Result proves that the color removal rate decreases with the kinds and structure of dye as follows:acid dye, direct dyes, disperse dyes, reactive dye, cationic dyes; and mono azo pigments>disazo pigments>trisazo dye>anthraquinone dyes>mono azo metal complex pigments>cationic dyes.To explore the mechanism of micro-electrolysis, a preliminary studying and verifying has been done by the comparison test of direct flocculation and iron-carbon micro-electrolysis. The mechanism of micro-electrolysis is mainly based on electrochemical reaction, however, flocculation and deposition just play a supporting role in the process.From the experimental data analysis, using the micro-electrolysis to treat the poor biodegradable dye wastewater can effectively reduce COD and the chroma, and improve the biodegradability of the wastewater and resulting in the benefit to the follow-up biological treatment. It has great economic and environmental benefits on the low processing cost and the principle of so called waster control by waster itself. So it has great development prospect.